Setting up a mail filter in front of Exchange (spam filter)

swgeckoman

We use MS Exchange in my office. I'm wanting to use something like DSPAM or SpamAssassin to filter out some of the spam before the users get it.

My current situation is an Imail server that receives mail for our organization, scans for viruses, and then forwards it in to the Exchange box. That's how it was when I got here. Every user has an alias on the IMail box that forwards to their username@exchange.company.com

I want to replace IMail with a Linux box that can scan the mail for viruses (probably sophos) and then drop off the more obvious spam-related emails.

Any suggestions?

georwell · Posted: Tue Feb 24, 2004 7:59 pm Post subject:

Checkout MailScanner. It can do what you want and a crapload more.

I don't know if there is an official ebuild yet but I know one exists in bugs.gentoo.org

kashani · Posted: Tue Feb 24, 2004 10:46 pm Post subject:

There are a number fo howto's for Linux based mail installs for adding spam tools to your MTA. Look around at the major sites for your MTA, here's a few I referenced for Postfix.

http://advosys.ca/papers/postfix-filtering.html
http://www.geekly.com/entries/archives/00000155.htm

Doesn't Imail support smtp routes like every other mail server? Normally you can forward an entire domain without having to go through the rigamarole of adding aliases for everyone. I do recall Imail sucking an incredible amount, but surely it can at least do this:

domain.com ---> exchange.domain.com

kashani
_________________
Will personally fix your server in exchange for motorcycle related shop tools in good shape.

swgeckoman · Posted: Thu Feb 26, 2004 8:08 pm Post subject:

Well, originally the users POP'd their mail, and internal mail was routed through exchange. When I got here, I started migrating users to Exchange only, and aliased each user when I deleted their mailbox. Now that everyone's mailbox has become an alias, I can just forward the whole domain. But I want to dump Imail and use a Linux box with sendmail or postfix to scan the mail for viruses and spam.

Hope that makes things a bit clearer.

georwell · Posted: Fri Feb 27, 2004 10:04 am Post subject:

You can use mailscanner for what you want to do. You will need to setup the mailertable for your domain. Other then that you should be able to keep your setup the same...

/etc/mail/mailertable
yourdomain.com smtp:[echange_ip]

mailscanner (sendmail, spamassassin, sophos) --> exchange.

If you look in the FAQ you can see an example of this and there is a new example of rejecting emails that don't have legitimate addresses before they hit the exchange server. You really should look at mailscanner it is really easy to setup and very powerful. If this doesn't meet your needs I must not understand you...

Why I am giving a *possible* missouri tiger help I don't know....

[EDIT] I forgot to say it has great Sophos (among other virus scanners) support and has scripts for automatic upgades and IDE downloading. [/EDIT]

Links:
http://www.sng.ecs.soton.ac.uk/mailscanner/serve/cache/152.html
http://www.sng.ecs.soton.ac.uk/mailscanner/serve/cache/270.html